Methods for supplying fibrous insulating materials by injection under air pressure provide a generally economical method of insulating a desired space. Such methods are economical at least partly because relatively inexpensive fibrous materials such as cellulose, or mineral fibers, fiberglass and the like can be used, as described, for example, in U.S. Pat. No. 4,487,365, issued Dec. 11, 1984, to Sperber; U.S. Pat. No. 4,530,468, issued Jul. 23, 1985, to Sperber; U.S. Pat. No. 4,712,347, issued to Sperber; and U.S. Pat. No. 4,768,710, issued Sep. 6, 1988, to Sperber and also because of the relative speed with which the insulation can be injected under air pressure compared with the installation of batt-type insulation.
There are two primary methods for supplying fibrous insulating materials by injection under air pressure. In the first, insulation particles mixed with adhesive are inserted into the space between the outer and inner walls of the structure. Since it is desirable to "blow in" the insulation particles and adhesive mixture prior to the construction of the inner walls, a retaining means, as described, for example, in U.S. Pat. No. 4,712,347, by Sperber, issued Dec. 15, 1987, is typically used to retain temporarily the insulation between the wall framing until the inner wall can be constructed to act as a permanent retaining barrier.
The process of blowing-in fibrous insulation has at least one major drawback. The process typically produces insulation with non-homogeneous density. The nonhomogeneity is caused both by the later portions of blown-in insulation impacting and compacting the first portions of blown-in insulation and by the settling of the fibers over time. In general, compacted or densified fibrous insulation has a lower insulating capacity compared to less dense or uncompacted fibrous insulation. Although an adhesive can be used to assist in maintaining the loft of fibrous insulation, as described in U.S. Pat. Nos. 4,487,365; 4,530,468; and 4,712,347, above, the adhesive may have insufficient time to set, cure or dry before impaction from succeeding portions of insulation occurs and may have insufficient strength to withstand the force of impact from succeeding portions of blown-in insulation. Additionally, the adhesive by itself may not be sufficiently spread or mixed with the fibers to provide the desired separation of the fibers.
In the second method for supplying fibrous insulating materials by injection under air pressure, lofted fibers of insulation are mixed with a foam to provide a blown-in fibrous insulation which has a substantially homogeneous density, providing for uniformity of insulation, as disclosed in U.S. Pat. No. 4,768,710. The lofted insulation fibers are created by the mixture of substantially dry fibrous particles with pressurized air. Similarly, the foam is created by the mixture of a foaming agent with pressurized air. The foam and lofted fibers are then introduced into the mixing chamber of a nozzle. Although not discussed in the '710 patent, a single mixing hose is typically connected to the nozzle. The inside diameter of the mixing hose is greater than that of the nozzle outlet. In the mixing chamber and mixing hose, the foamed material is mixed with the lofted fibers so that the foam maintains the loft or the desired spreading of the insulation fibers relative to each other. The length of mixing hose can be approximately two feet. The mixture of fibers and foam material is carried under pressure away from the mixing hose into the desired space, but without any velocity, where the foam maintains the desired loft or spreading of the insulation fibers to achieve a uniform density of the insulation over time.
Like the first method, the apparatus and method of U.S. Pat. No. 4,768,710, has a significant limitation. The apparatus does not eject the foam/insulation mixture with sufficient velocity to cause the mixture to adhere to a surface, even though an adhesive material has been incorporated into the mixture. Rather, as in the first method, placement of the mixture requires the use of some means to retain temporarily the insulation between the wall framing until the inner wall can be constructed to act as a permanent retaining barrier.
In contrast to loose fibrous insulation, insulation comprising a solid "foam" is used in some applications. Although fibrous material can be incorporated into such foam as crystallization sites, fillers, reinforcements and/or pacifiers, as described in U.S. Pat. No. 4,402,892, issued Sep. 6, 1983, to Helser, it is the solid foam itself, rather than the fibers, which produces the insulation effect. To enable such insulation to fill a void, it is first produced in a fluent form and then cured or dried to form the solid foam. Thus, the fluent foam must be capable of substantial solidification into a permanent body. Materials which are capable of this solidification such as a cementitious material, as described in the Helser patent, or resin materials as described in U.S. Pat. No. 4,103,876, issued Aug. 1, 1978, to Hasselman, Jr. et al. and U.S. Pat. No. 4,135,882, issued Jan. 23, 1979, to Harkness et al. are typically more expensive than fibrous insulation materials. Furthermore, many solid foam insulation materials require relatively expensive and time-consuming additional steps to accomplish curing or drying, such as a heating step.
U.S. Pat. No. 4,447,560, issued May 8, 1984, to Piersol describes forming a fibrous sheet by agitating a mixture of a foamable solution and a slurry of binder-coated insulation fibers to homogeneously suspend the fibrous slurry. The present invention differs from the subject matter of the Piersol patent in several important respects. First, unlike the Piersol patent, the present invention does not utilize a slurry of fiber and binder materials but requires the use of pressurized air to provide spreading of insulation fibers to achieve a desired degree of fiber "fluffiness." Second, the foam material desired herein is already in its agitated state when it is mixed with the fibers. Third, the insulation mixture of the present invention is directly sprayed under pressure into a formed cavity at a building construction site; there is no formation of a batt-type insulation or a standard sheet of fibrous material. Finally, there is no step of heating for drying purposes after the insulation material is located in the cavity.
A common denominator for insulating methods using either blown in fibrous insulation or solid foam or batt-type insulation is the substantial construction labor and materials required to provide a structure to accommodate the insulation. For example, for loose fibrous insulation, a building contractor first typically constructs a cavity for the insulation by attaching a temporary retaining structure to a series of studs spaced at regular intervals in the wall. After the fibrous insulation is inserted into the cavity, a permanent retaining structure, such as drywall, is nailed to the studs. Expensive fire retardant drywall is sometimes used to decrease fire danger. To provide a wall amenable to finishing such as painting or wallpapering, a drywall finisher must fill and finish not only the seams between the drywall panels but also each of the innumerable nail indentations in the drywall. Not surprisingly, this process is time and labor intensive and substantially increases already high construction expenses.
Insulating methods using either solid foam or batt-type insulation are even more expensive than loose fibrous insulation. A building contractor must not only perform the above-noted construction steps (with the exception of the erection of a temporary retaining means) to accommodate the insulation but also use must incur additional expenses required to manually install the insulation in a wall cavity. For example, batt-type insulation is typically inserted into a cavity and then stapled to the surrounding studs. Additionally, solid foams require relatively expensive and time-consuming steps to accomplish curing or drying, such as a heating step.
Based on the foregoing, there exists a need for method for applying insulation that reduces the costs associated with present methods of installing insulation. More specifically, there is a need for a method of applying insulation that substantially eliminates, the need for the construction of a retaining structure. It would be particularly advantageous to have a method to apply insulation in which the insulation could be molded, preferably substantially simultaneously with its application to desired shapes and textures. Further, there is a need for an insulating method that, in appropriate circumstances, eliminates the need for a permanent retaining structure, such as drywall. Stated another way, there is a need for a method of insulating that produces an insulating structure that can also serve as a wall, ceiling, or like structure which can be painted, wallpapered or otherwise textured. Further, in the situations in which the use of drywall or similar surfaces is appropriate, there is a need for a method of insulating that reduces the costs associated with the hanging and finishing of drywall. Additionally, there is the further need for an insulating method that reduces the costs associated with providing a fire resistant structure. Moreover, there is a need for a method of insulating that can reduce costs associated with painting the structures that presently overlay the insulating layer in a building. Finally, there is a need for an insulation which can not only adhere to a wall but also can have its strength and insulating properties altered to correspond with the needs of specific applications.